Haiti is facing further political disarray after fraud allegations forced authorities to delay certifying results from last month's legislative election.

The provisional electoral council said it would not publish 19 seats' results following criticism from the UN, US, and the incoming president, Michel Martelly.

Some Haitian politicians demanded a recount, others a fresh election. There were also calls for a travel ban on members of the electoral council, some of whom resigned over the row.

The complaints centred on irregularities in the counting of votes in the runoff which seemed to favour the Unity party of the outgoing president, René Préval. The party was awarded 46 of 99 seats in the chamber of deputies and 17 of the senate's 30 seats.

"We have found no explanation for the reversals of 18 legislative races in the final results, which in all except two cases benefited the incumbent party," the US embassy in Port-au-Prince said in a statement. "Without a public explanation and review … the legitimacy of seating these candidates is in question."

The embassy cited one case in which votes for one Unity candidate jumped from 90,000 in preliminary results to more than 145,000 in final results.

Gaillot Dorsinvil, head of the electoral council, said the results of 19 seats in total would not be certified out of "transparency" but he did not mention a recount nor details of what may happen next.

The row could delay Martelly's scheduled inauguration on 14 May and planned constitutional reforms, which are supposed to be voted on by 9 May.

Martelly, who won March's presidential runoff, said he expected the problem would be resolved within weeks but called for an independent Haitian-led investigation into electoral processes.

The carnival singer-turned politician, fresh from US secretary of state Hillary Clinton's backing on a trip to Washington, went to Miami to lobby Haiti's diaspora for help in rebuilding the earthquake-shattered Caribbean country. "We need you to bring your skills and expertise back to Haiti," he said.

He proposed diverting 1% of wire transfers to Haiti, and a 5 cent a minute levy on phone calls, to an education fund to give 860,000 impoverished children free schooling.

Even before the January 2010 quake, which destroyed many schools and killed numerous teachers, Haiti struggled to educate all its children. "Education is the future of Haiti," said Martelly.